The Finnish Meteorological Institute, the Alfred Wegener institute and Bremen University jointly performed upperatmospheric soundings from Ny-Ålesund, Spitsbergen (79-degrees-N, 12-degrees-E) between March 11 and April 24,1991. The soundings were made using Vaisala radiosondes and ECC ozone sondes and produced a good picture ofozone behaviour in the lower and middle stratosphere. With one exception, the soundings were carried out daily or atleast every other day with most of them reaching altitudes higher than 30 km. - The temperature record reveals that in themiddle of the experiment stratospheric warming took place. The warming was also reflected in the rising trend of totalozone, in addition to this transition from winter to spring conditions in the polar stratosphere, there was also considerablevariability in both the total ozone content and the vertical variability of ozone concentrations. The reasons for these seemto be to a large extent dynamical in origin.